I’m just now catching up after a busy week in Anaheim at SPI 2018. Array Technologies had prime real estate for our two-story booth at the entrance to the show and I am pleased to say that there was no shortage of colleagues (both new and old) that came by to chat and check out the latest in tracker technology. I’m not sure if more business got done in the booth or at the Anaheim Hilton bar. You could find half of the conference attendees in the Hilton at any time day or night. Anaheim turned out to be a great host, although many SPI veterans missed the Block Party being held at Disney like in years past. There is something special about watching your customer scream in terror on Space Mountain that brings everyone together!
Tracker Wind Studies: Useful or A Lot of Hot Air?
At SPI, there was a buzz around Wind Tunnel Studies for trackers. These studies used different methods of wind testing to demonstrate that a tracker stowing at zero degrees is the most unstable, and leaves the tracker susceptible to wind and even torsional galloping (harmonic forces that twist structures, like the Tacoma Narrows bridge). These studies recommend a high-angle stow with dampers.Array Technologies is no stranger to Wind Tunnel Studies, originally completing our first in 2008.
Our studies agree with the high stow angle and damper premise and we believe it is an overall positive for the industry that Wind Studies are taking place more frequently. It is great for the solar industry as a whole when Utility sites make it through hurricanes without damage and keep on running. However, many recent wind studies miss a major risk factor when considering weather events: they assume that the tracker is at a high-angle stow position during wind events. To get to the optimal high-angle position for stability in wind conditions, some tracker technologies are dependent on electrical stow. If these trackers don’t reach their expected stow position, the tracker will be susceptible to wind events.
With Array’s vast experience, we’ve found that electrical stow is not the way to go, so we’ve migrated away from it. Why? Because of the old saying – a system is only as strong as its weakest link. “Active” stow, AKA electrical stow systems, have a lengthy command chain, and every link in the chain must be functioning properly in order for the system to reach stow. All of the following components have to function correctly for an electrical stow to occur: anemometer, batter for the controller, coaxial controller panel supply, wireless radio, central controller electronics, row controller electronics, row controller power supply, and row controller motors. That is a lot of components to rely on to ensure your tracker makes it to a safe position.
Array’s design philosophy is fundamentally different. It is to build a tracker that withstands the full site wind speeds at any angle without relying on stow. Array stabilizes wind loads through an automatic, failure-free mechanical wind management system. Our gearbox torsion limiter allows each row to self-adjust to its position of least force in a wind event, while the rest of the block continues to track.
Redundant mechanical stops are integrated in each foundation post and gear rack which hold the tracker row in a safe position and distribute loads evenly. At full wind, the tracker naturally adjusts to the high-angle position that is the safest according to wind studies. The same mechanism allows for automatic recalibration of each row twice daily – not to mention rapid commissioning after installation.
Evening the Playing Field (Terrain)
How does the old Sound of Music song go? “The Hills are Alive with the sound of Array Technologies Trackers…”
Maybe that isn’t exactly how the original song was recorded, but the point is that Array trackers are extremely flexible for use in undulating terrain or hilly sites. At SPI, you could see up to 40° of extreme driveline flexibility on display in our booth. Long gone are the days when single-axis trackers require a flat site. To that, we say – HILL YES! (And yes, we do really say that, in fact, we printed T-shirts).
The unsurpassed flexibility of our system allows you to install solar where it would not be feasible otherwise and saves you money by avoiding grading costs all together. Undulating sites can also introduce shading of modules in the late or early morning hours. At SPI, Array Technologies introduced our SmarTrack™ optimization technology.
To alleviate a shading effect, SmarTrack monitors power production and utilizes a machine learning algorithm that mitigates shading by backtracking to optimal angles. Once an operational strategy has been learned for a specific site, power production is boosted on a daily basis.
SmarTrack also is able to optimize production during cloudy conditions with Diffuse Lighting Optimization and has the ability to customize the backtracking algorithm for bifacial modules. If you missed SmarTrack at our booth at SPI, give us a call and we would love to speak more about it. It is important to remember that real-world sites require real-world assessments. Our team of trained engineers will work with you to find the optimum configuration of these benefits based on the unique qualifications of your site.
See you again soon!
As always, it was great seeing all of our colleagues, customers and partners at SPI 2018. We have a little break until the next big Solar conference, so in the meantime; come out and see us in Albuquerque or have Array Technologies come out to your site and see how we can help!